COMPARISON OF THREE RADIOGRAPHIC CONTRAST PROCEDURES IN THE EVALUATION OF THE CANINE LUMBOSACRAL SPINAL CANAL

Lumbar myelography, intraosseous caudal vertebral venography, and epidurography were performed in 12 normal, mature mixed-breed dogs. The radiographic appearance of the lumbosacral region was evaluated in both the lateral and ventrodorsal projections. These three radiographic contrast procedures were repeated in the same dogs after the introduction of a silicone mass into the spinal canal at the lumbosacral junction. The radiographic findings were compared with postmortem findings to determine which contrast procedure was most useful in detecting the mass in the lumbosacral spine. None of the procedures evaluated consistently produced good-quality studies in the normal dogs. After introduction of the silicone mass, lumbosacral epidurography yielded the largest number of positive correlations. However, the sensitivity of lumbosacral epidurography was less than 50% in the lateral projection and less than 20% in the ventrodorsal projection. Though none of the procedures were consistently helpful in the diagnosis of the lumbosacral masses, lumbosacral epidurography has the most potential to give consistently good-quality studies and thereby a greater probability of detecting an abnormality.     

The liver in systemic disease. An innocent bystander

The role of the liver in maintaining the health and function of other organs is frequently described in pathophysiologic terms. A large volume of information has been gleaned on the biochemistry and physiology of the "primary" hepatic diseases. In the dog, there is a paucity of information about the chemical events essential to the viability of normal liver cells and, more specifically, the mechanisms by which diseases of other organs secondarily affect the liver.     

Pre-breeding Ovaro–Uterine Ultrasonography and its Relationship with First Service Pregnancy Rate in Seasonal-Calving Dairy Herds

The objectives of the study were to characterize an ultrasound reproductive tract scoring (URTS) system to assess suitability for breeding in dairy cows, to describe the prevalence of these scores in commercial dairy herds and to examine their relationship with subsequent fertility. Ultrasound examinations (7797) were performed on 5751 Holstein–Friesian cows prior to breeding in 62 seasonally calving herds over 2 years. Data recorded from images of both ovaries and the uterus were combined into a six point scoring system and the prevalence of cows with cystic ovarian follicles and uterine abscesses and adhesions was recorded separately. The prevalence of ovulatory cows which had completed uterine involution (score 1), or had mild (2) or moderate endometritis (3) was 62.5%, 21.7% and 2.2%, respectively. The prevalence of anovulatory cows with moderate endometritis (4), ovulatory cows with pyometra (5) and anovulatory cows which had completed uterine involution (6) was 3.3%, 2.2% and 8.1%, respectively. The interval between calving and examination differed between cows with each of the scores 1, 2, 5 and 6 (61, 46, 53 and 50 days, respectively, p < 0.05) but not between cows with scores 3 and 4 (37 and 35 days, respectively). Ovulatory cows which had completed uterine involution (score 1) had a higher likelihood of pregnancy to first service than ovulatory or anovulatory cows which had not completed uterine involution (p ≤ 0.10). The prevalence of cows with cystic ovarian follicles or abscesses or adhesions of the reproductive tract was 3.9% and 1.2%, respectively. In conclusion, 29% and 11% of cows in seasonally calving and breeding dairy herds had not completed uterine involution or were anovulatory prior to the mating start date, respectively. Both conditions, detected using a URTS system, significantly reduced first service pregnancy rate in these pasture-based dairy herds.     

Incubating Rainbow Trout in Soft Water Increased Their Later Sensitivity to Cadmium and Zinc

Water hardness is well known to affect the toxicity of some metals; however, reports on the influence of hardness during incubation or acclimation on later toxicity to metals have been conflicting. We incubated rainbow trout (Oncorhynchus mykiss) near the confluence of two streams, one with soft water and one with very-soft water (average incubation hardnesses of about 21 and 11 mg/L as CaCO₃, respectively). After developing to the swim-up stage, the fish were exposed for 96-h to a mixture of cadmium (Cd) and zinc (Zn) in water with a hardness of 27 mg/L as CaCO₃. The fish incubated in the higher hardness water were about two times more resistant than the fish incubated in the extremely soft water. This difference was similar or greater than the difference that would have been predicted by criteria hardness equations had the fish been tested in the different acclimation waters. We think it is plausible that the energy demands for fish to maintain homeostasis in the lower hardness water make the fish more sensitive to metals that inhibit ionoregulation such as Cd and Zn. We suggest that if important decisions were to be based upon test results, assumptions of adequate hardness acclimation should be carefully considered and short acclimation periods avoided. If practical, incubating rainbow trout in the control waters to be tested may reduce uncertainties in the possible influences of differing rearing water hardness on the test results.     

Effects of calving age, breed fraction and month of calving on calving interval and survival across parities in Irish spring-calving dairy cows

The objective of this study was to investigate the effect of parity, age at calving, percentage North American Holstein-Friesian and calving date on subsequent calving interval and survival to facilitate the estimation of transition probabilities for month of calving. The economic value of traits that influence calving date, age distribution and survival can be assessed in models using a transition probability matrix. Such a matrix contains the probabilities that a cow of a particular age or breed calving in a particular month will calve in the same, an earlier or later month next year, or be culled. Following editing 1,046,855 calving records in spring-calving herds between the years 1990 and 2004 were analysed. Shorter calving intervals were associated with cows calving later in the calendar year. Age at first calving of < 24 months resulted in longer calving intervals to second calving across all levels of Holstein percentage with cows calving for the first time at 25–26 months of age having the shortest subsequent calving interval. Age at second calving of 37–38 months and third calving of 49–50 months were optimum for shorter subsequent calving intervals. Calving interval increased with Holstein percentage across the first 5 parities. Survival rate decreased with later month of calving and with older parities. When survival rate was measured as the ability of the cow to re-calve within 500 days, the highest survival rate was found in cows calving at 25–26 months of age whereas there was a noticeable reduction in survival across all parities in the 88–100% Holstein percent category.     

A cDNA for a protein that interacts with the human immunodeficiency virus Tat transactivator

The human immunodeficiency virus (HIV) tat protein (Tat) is a positive regulator of virus gene expression and replication. Biotinylated Tat was used as a probe to screen a lambda gt11 fusion protein library, and a complementary DNA encoding a protein that interacts with Tat was cloned. Expression of this protein, designated TBP-1 (for Tat binding protein-1), was observed in a variety of cell lines, with expression being highest in human cells. TBP-1 was localized predominantly in the nucleus, which is consistent with the nuclear localization of Tat. In cotransfection experiments, expression of TBP-1 was able to specifically suppress Tat-mediated transactivation. The strategy described may be useful for direct identification and cloning of genes encoding proteins that associate with other proteins to modulate their activity in a positive or negative fashion.     

Use of phosphonic acid as a generic hapten in the production of broad specificity anti-organophosphate pesticide antibody

Phosphonic acid (trans-4-phosphono-2-butenic acid; TPB) was used as a generic hapten in order to generate broad specificity antibodies against a group of organophosphorus pesticides. The polyclonal antiserum showed, in an indirect enzyme-linked immunosorbent assay (ELISA) format, preferential binding toward pesticides containing unsaturated diethyl-phosphate functionalities rather than the equivalent thiophosphate or dimethyl structures. The level of detection in the ELISA using a heterologous system was investigated and showed a 20-fold improvement when a conjugate for which the antibody had lower affinity was immobilized on the plate. Biosensor assays using parathion as a standard indicated that the antibody had a relatively high dissociation rate, and reproducible cycles of regeneration were achieved. The potential for using TPB as a generic hapten is discussed.